Transmission code
P0720: Transmission output speed sensor problem
How this range is built
| Part of the job | Low | High |
|---|---|---|
| Parts | $40 | $200 |
| Labor: 0.7 to 1.5 hours × $125 to $175 an hour | $88 | $263 |
| Fees: shop supplies, disposal, diagnostics | $0 | $20 |
| Total, rounded | $120 | $490 |
The hourly rate is the BLS Occupational Employment and Wage Statistics, May 2025 average pay for this trade in Boston, $31.54 an hour, times 4 to 5.5 to cover what a shop bills (overhead, tools, insurance, profit). Parts are a band from budget aftermarket to the manufacturer part. Full method.
Not a repair shop, estimates only. Typical range, estimate. Not a quote. Your car, parts and shop change the number.
This is the range for the most common fix, transmission speed / range sensor replacement. Which repair your car needs depends on a proper diagnosis.
The output speed sensor reads how fast the shaft leaving the transmission is turning. The computer cannot get a good signal from it, so it cannot decide when to shift or lock the torque converter. On many cars the speedometer also depends on this signal.
- Safe to drive?
- Short trips only
- Most common cause
- Failed output speed sensor
You can often limp to a shop, but shifting may be harsh and the speedometer may be off. Avoid highway driving until it is fixed.
What you may notice
- Speedometer jumping or dead
- Harsh or late shifts
- Stuck in one gear
- Check-engine light
Common causes, most likely first
- Failed output speed sensor
- Damaged wiring or connector
- Metal debris on the sensor tip
- Internal transmission damage (less common)
Check this first
Look at the sensor connector for fluid or corrosion. Ask if the transmission fluid has been checked for metal particles.
Other repairs that sometimes fix P0720
| Repair | Typical range, Boston |
|---|---|
| Diagnostic scan (check engine light) | $60 to $290 |
| Transmission fluid service | $150 to $520 |
| Wheel speed sensor replacement | $120 to $360 |
Before you pay
- Ask the shop what test showed this part is the cause, not just that the code appeared.
- Ask for parts and labor listed separately, and for the hours.
- Ask for a written OK before any extra work. Massachusetts rules require written authorization before repairs.
Got a quote already? Check it against the range. Want to see if your car has a recall tied to this problem? Check recalls by VIN.
Need to read a code yourself? OBD-II scanners on eBay (affiliate link, disclosure).
P0720 questions
Why is my speedometer wrong?
On many cars the speedometer reads from the same speed signal, so a failing sensor makes the needle bounce or drop to zero. That is a useful sign for the shop to start with this part.
Is this expensive?
Sensor swaps are usually on the low end of transmission work. Labor depends on where it sits, since some are easy to reach and others need parts removed or fluid drained.
Can bad fluid cause it?
Dirty fluid carrying fine metal can coat the sensor tip and weaken its signal. A fluid check is worth asking for, because metal in the fluid also points to wear that a sensor swap will not fix.
How much does it cost to fix P0720?
The most common fix, transmission speed / range sensor replacement, has a typical range of $120 to $490 in Boston. It is an estimate built from parts prices and local labor wages, not a quote. Your car and shop change it.
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Code meaning written in our own words. Some codes mean different things on different makes, so check your scan tool or manual. Not a repair shop, estimates only.